The erection of structures utilizing suspension cables or Cable-Stay Technology has existed for some time. For example, many bridges utilize cables extending between towers or from a single tower to suspend a roadway. In addition, many buildings have been designed such that the roof structure is supported by cables. The principal advantage of utilizing cables to support a roof is that large covered buildings can be designed without any internal supports; and quite economically. One example of a structure which benefits from this type of design is an airplane hanger which requires a large area without pillars to permit positioning aircraft. Sporting arenas also benefit from this design since the design provides for unobstructed viewing.
Examples of roof structures designed by the applicant with Cable-Stay Technology can be found in the following design U.S. Pat. Nos.: D260,036, issued Jul. 28, 1981; D270,570, issued Sept. 13, 1983; D 274,841, issued Jul. 24, 1984; D274,842, issued Jul. 24, 1984; D274,843, issued Jul. 24, 1984; and in current utility U.S. Pat. Nos. 4,651,496 issued Mar. 24, 1987 and 4,802,314 issued Feb. 7, 1989.
The design patents above relate to the ornamental appearance of Cable-Stay supported structures.
The utility patents above relate to methods of construction of Cable-Stay roofs over existing stadiums or arena and their design.
Also made reference to is pending design patent application filed May 8, 1987 under Ser. No. 047,064 which covers the ornamental appearance of the Cable-Stay supported structure in utility patent U.S. Pat. No. 4,802,314.
The invention of this application relates to the construction of a Cable-Stay roof over an existing or new stadium or arena, or other structure and to the method of its construction.
Recently there has been significant amount of interest in covering existing as well as new open air athletic stadiums. As can be appreciated, many stadiums are located in areas where weather conditions make it difficult to hold events whenever desired.
Existing open air stadiums are generally not designed to support the weight of a newly added roof. Thus, in order to build a roof over an existing stadium, significant measures have to be taken to reinforce the stadium walls or build an additional support system. The latter steps, even if possible, can be difficult and expensive. With new stadiums this can be less of a problem.
There has been significant interest in making these roofs retractable or at least openable for ventilation.
Also there has been interest in providing means of retaining a natural grass playing field on the stadium floor both in existing stadiums as well as in new stadiums.
Accordingly, it is an object of the subject invention to provide a new and improved method for constructing such a roof over an existing or new stadium or arena, or other structure.
It is an object of this invention to provide a means of constructing such a roof that is both functional and cost effective to build.
It is an object of this invention to provide a new and improved method of constructing a cable roof structure over an existing or new stadium or arena, which structure will provide unobstructed viewing within the stadium.
It is still another object of this subject invention to provide a new and improved method of constructing a cable roof structure over an existing or new stadium, which structure is capable of supporting a glass or a clear plastic roof cover to allow for the retention or use of a natural grass cover on the playing field and to provide as well for the public enjoyment by creating an outdoor atmosphere.
It is also another object of this invention to provide a new and improved method of constructing a Cable-Stay structure over an existing or new stadium, which structure is capable of supporting a partially retractable cover or one that opens sufficiently for ventilation.
It is further the object of this invention to provide a roof that allows for natural ventilation by keeping parts permanently open such that costly heating and air handling equipment might not be necessary.
It is further the object of this invention to provide a clear skylight roof cover such that costly additional lighting is not necessary in an existing stadium where tower lighting exists and can project through the skylight roof. It is also the object of this invention to provide a roof that could support a restaurant and/or sightseeing walkways on its surface.
It is also the object of this invention to provide a roof that could support luxury private seating boxes suspended from the roof structure.
It is also the object of this invention to provide a roof that is structurally sound to withstand, besides its own weight and design loading, also high earthquake forces and unusual wind forces, and snow loading.
It is also the object of this Invention to build a roof that can be built by available technology and contractor's experience, available in the marketplace.
It is also the object of this invention to provide a roof that is permanent and has a long life.
It is also the object of this invention to provide a roof that has relatively low operating and maintenance costs.
It is also the object of this invention to provide a roof that can be aesthetically pleasing.
Another and more specific object of the invention is to provide a roof structure and method of fabricating the same wherein first and second Cable-Stay suspended sections of the structure are cantilevered toward one another from oppositely disposed towers and an intermediate section of the structure is Cable-Stay suspended between the first and second sections without imparting significant cantilever loads to the towers.
Another and more general object of the invention is to provide a roof structure including cantilevered sections wherein cantilever loads are reduced by suspending a portion of the structure in tension from Cable-Stays.